US patent application US2002/0084748A1 discuses a light source that is suitable for general illumination, which means for the illumination of spaces that may be too dark for people to stay or work in. The light source comprises a light emitting diode (LED) that emits UV light. Phosphor material is used to convert the phosphor material towards visible light that is emitted into the ambient for illuminating the environment. Near a light exit window, a material is provided that reflects non-converted UV light back to the phosphor material for conversion such that no UV light is emitted into the ambient.